It's been my experience if you really need that type of range the GIV will pretty much do it all
The big question is are you attempting to cover 3000 nautical ground miles or 3000 nautical air miles, the difference between the two is the wind. And are you expecting to do it 100% of the time.
I have flown a GIV with a ground speed of 300 kts, hence making a 3000 ngm sector impossible.
So I would suggest that you define your routes, set about finding the average winds and then decide on your requirements.
Mutt